PM0214 datasheet(87/245 Pages) STMICROELECTRONICS

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PM0214

The STM32 Cortex-M4 instruction set

244

Examples

CLZ R4,R9

CLZNE R2,R3

3.5.5

CMP and CMN

Compare and compare negative.

Syntax

CMP{cond} Rn, Operand2

CMN{cond} Rn, Operand2

where:

•

‘cond’ is an optional condition code (see Conditional execution on page 64)

•

‘Rn’ is the register holding the first operand

•

‘Operand2’ is a flexible second operand (see Flexible second operand on page 59) for

details of the options.

Operation

These instructions compare the value in a register with operand2. They update the condition

flags on the result, but do not write the result to a register.

The CMP instruction subtracts the value of operand2 from the value in Rn. This is the same

as a SUBS instruction, except that the result is discarded.

The CMN instruction adds the value of operand2 to the value in Rn. This is the same as an

ADDS instruction, except that the result is discarded.

Restrictions

In these instructions:

•

Do not use PC

•

Operand2 must not be SP

Condition flags

These instructions update the N, Z, C and V flags according to the result.

Examples

CMP R2, R9

CMN R0, #6400

CMPGT SP, R7, LSL #2

PM0214 数据表(PDF) 87 Page - STMicroelectronics

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